1. Field of the Invention
The present invention relates to an imaging apparatus, and more particularly, to an imaging apparatus that includes solid-state image pickup elements.
2. Description of the Related Art
A solid-state imaging apparatus has been proposed that uses a line memory to perform vertical and horizontal addition of signal charge when reading out signal charge accumulated in pixels of solid-state image pickup elements (see Japanese Patent Application Laid-Open No. 2003-264844).
For example, with a camera capable of high-sensitivity picture taking, when its focus is adjusted in a low-light environment, pixels that are vertically added will be increased in order to obtain luminance required for focusing. This leads to problems of reduction of resolution mainly in the vertical direction and hence reduction of accuracy of focusing detection and/or exposure control.